Guiding means for grinding drills



A. c. MOOREFIELD GUIDING MEANS FOR GRINDING DRILLS Filed Feb. 9, 1943 facilitate the setting of Patented Oct. 23, 1945 UNITED STATES PATENT OFFICE i 2,387,459

GUIDING MEANS Fort GRINDING DRILLS AlbertG. Moorefield', Hawthorne, Calif. Application February 9, 1943, Serial No. 475,245 9 Claims. (01. 51-219) j This invention relates to guiding means for facilitating; the grinding Of points of drills. The

grinding: oithepoints of drills, and particularly those of small diameter, is a source or considerable. .diillculty and Shops; as his very diflicult to hold and properly support a drill of smalldiameter when grinding its- :point, and it usually requires considerable, practice to. develop sumcient skill in a mechanic properly grind a drill-points where skilled mechanics are to enable. him to Furthermore, even employed, the personal equation enters very largely: in the grinding operation, the result of which, is that the drills are not uniformly sharpened.

The drills referred to are a type known as'twist inconvenience. in machine drills, and the bodies of these drills have a high pitch helical groove extending down the same to i a point, which is substantially conical", but with the cone point ground in slightly from the cone back of the cutting: edge.

An. object .oftthe present invention is to providc uiding means including a rest andmeans cooperating with the rest in order to facilitate the: grinding of, a point or a twist drill such as referred to above. i a

. Another objectof the invention isto provide a rest with means cooperating with the same to adaptthe rest to the grinding of the points of the drills of different diameters.

Another object of the invention .is to provide uidmgmeans including the/rest and a holder with coordinated means on the rest and on the holder for facilitating the grinding of the drillpoint by applying the same to the rest, and

.movingtheholder laterally while. guided on the rest to effect the grindingoperation on the drillpoint.

Another objector the invention is to provide means on theholder for the drill, which will the drill-point as regards the: length to which it extends from the holder,

so as to enable the same to, cooperate with the rest when the drill-point is being ground;

Another object ofth'e invention is to provide the holder with simple means/for insuring that when the holder and the drill are applied to the rest, the drill will be prevented from rotating on its. own axis, thereby'insuring uniform grind-- of the drlll-point and precisely at the areas desired. i 1

Further objects of the invention will appear hereinafter. r

The invention consists in the novel parts and combination of. Parts to be: described hereinafter.

all of which contribute to produce an eificient broad scope of the invention is pointed out in the appended claims.

In the drawing: Fig. 1 is a plan. of a portion of. a tool ri der.

certain parts being broken away, and illustrating .a drill-rest and guiding means embodying my invention, and supported adjacent to the side face of the grinder wheel.

Fig. 2. is a section taken in an inclined plane disposed substantially at right. angles to the upper face ofthe. body or body-plate of the rest on which the drill; lies when being ground or sharpened. This view indicates a portion of the side face of the grinding wheel broken away and indicated in section, and in this view also the body of the holder for the drill, is broken away.

Fig. .3 is a planet the holder removed from the rest and illustrating a drill held in the holder with the gau e of the'holder positioned so that it will cooperatewiththe drill to indicate the proper degree of extension of the drill beyond the forward end. oriented position of, the drill on its own axis for proper grinding.

Fig. 4 is a cross-section taken on the line 4----4 of Fig. 3, and looking toward the rear end of the on its own axis away from the proper position,

in which it should be held.

Fig.6 is a vertical section taken about on the line 6-6 of Fig. l, and illustrating approximately the relation of the axis of the drill to the plane of the abrading face or side of the grinding wheel. In this view the body of the drill is broken away; a portion of the supporting edge of the rest is illustrated in section.

In practicing the invention, I provide guidin means which is preferably supported on a, shelf or horizontal plate I of a frame 2 that supports an abradingor grinding wheel 3. In practice, I prefer to attach my device so that the point of the drill 4 will be applied to the fiat side face 50f the grinding wheel. In the present instance, I provide a bracket 6 having a foot T that may be. attached on thesuppor-t or shelf l by any suitable means such as of the holder, and also the proper machine screws 5. This bracket 6 is formed with an upwardly extending shank 9 that flares out above to form a platelike extension or plate I which is formed with curved guiding means adjacent its outer edge, that is to say, the edge that is remote from the abrading face 5. In the present instance, I form this guide plate It with a curved edge II, the outer portion [2 of which is an arc struck on a radius, having its center substantially at the point l3 which would=be-substantial1y"at the point of intersection ,offthe axial line [4 of the drill 4 with the side face of the grinder when the drill is applied on the rest ready to be ground; the portion of this curve that approaches the grindin'g face 5 deviates, however, from this are so as to produce a cam edge [5 that permitsthe point l6 of the drill 4 to move nearer to the abrading face 5 if the drill is swung toward the right as viewed in Fig. 1. The inner edge ll of adjacentface of the chamber l9 may be provided this inclined plate H1, is substantially straight and liessubstantially-parallel'with the face 5 and quite close to it. t

The drill 4 ispreferably held in aholder l8 which is an elongated block as indicated in Fig. 3. In Fig. 3 the holder is viewed from itsunder side; The body of this holder has a chamber or socket I9 extending completely through'it to enable the drill to be inserted from one end and clamped therein by means of a set screw 26' (see. Fig. 4). The forward end or nose 2| of this holder is guided along the curved edge l2, 15, when the drill is being ground. And, moreover, the body [8 is provided with means for setting the drill so that it extends theproper amount for a prop-er grinding at the forward end of the holder. For.

this purpose I provide the body of the holder with a movable gauge 22 which, in the present instance, is of bifurcated form and secured pivotally to the holder by means of a pin 23 (see Fig. 4) that projects outwardly on each side, and which pivotally attaches the two forks of this gauge. At the outer end of the gauge a cross bar or cross-head 24 connects the two" forks, and the outer edge 25 of determined distance from the nose 2! of the body that the drill will be attached in the proper oriented position for grinding with ment, the edge 25 is provided with'a base mark 26. When the drill is set, this base mark should substantially register with the the drill-point, that is to say, the edge 21 is the cutting edge formed at the conical tip of the drill. After the drill-point has been set and clamped in the position illustrated in Fig. 3, the cross-head or stirrup'end 24 of the gauge 22, is then swung around on the pivot pins 23 so that this gauge occupies a reverse position as indicated in Fig. 1. In thisposition the drill should be laid upon the upper face of the plate It about perpendicular to face 5, and the holder I8 is then swung to the right to grind the point of the drill. After grinding the side of the drill-point that is then presented to the abrading face 5, the holder should be turned over to an inverted position with the set screw 20 located below, and this operation repeated.

The degree of the cone on the drill, is determined substantially by the angle formed between the axis of the drill and the vertical face 5 of the abrading wheel. This is indicated in Fig. 6 which is a section on the line 6-6 of Fig. 1. butt end of the drill is swung over toward the face 5, the cone face 28 of the drill is out back this stirrup 2 4 is at a pre-' 45 for setting the drill-point; andin order to insure 1 Ithisattachcutting edge 21 at face 28 that is formed 7 When the rear portion or to form necessary clearance to give the drill a proper cutting point. A skillful mechanic can hold the holder l8 accurately in the position indicated, and also exactly in an inverted position to this in sharpening the drill, thereby insuring uniformity because such a skilled drill grinder would not orient the drill on its axis in doing this except to invert the holder. But if desired, means may be provided for insuring that a me- 10 chanic not so skillful, will hold theholder fixed with respect to the axis of the drill in grinding it. For this purpose I may provide a collet or auxiliary holder 29 which is in the form of a piece of bent strap metal for presenting two forks 3'0 15 with a cross-head 3| connecting the same. This cross-head 3| has an opening 32 in it that fits substantially to the diameter of the drill being ground. 'I'he forks extend inwardly in the chamber [9, and if desired, these forks and the with yielding interlocking means forholding the collet 29 in placewhen it has been inserted. This 1 can be accomplished by pressing a depression r or rudimentary socket 33 into the outer face of 255 81131181 one or both of these forks 30, and forming a corresponding small projecting nib on the inner 7 face of'the socket or chamber I9; The forks 30 would .of course havesome resiliency and tend I to spread slightly so as to. cause "the socket 33- goiito engage the nib when the.col1et 29 has been" inserted sufiiciently far. into the holder [8.

In the inserted position of the collet 29,-its

forward end will project :slightly over the upper face of the upper plate ill in the manner indi- 35icated in Figs. 1 and 2, and as long as thegrinder holds the side of this collet down against' the upper face of the plate, no orientation of the drill on its longitudinal axis can take place.

In order to adapt the device for operating on form "of an upwardly projecting spur that proof the drill in the position in which it would be ina clearance slot 36a formed in the plate. Adjacent to this collar-136a neck 31 of reduced diammaterial of the neck is enlarged to forma dial sisting in holding this plate 38 in its proper alignmany position in which it is adjustedl' drills of different diameter and with'equal accuracy, I prefer to provide a center stop 34 in the placed on starting a' grinding operation. For 1 this purpos this centering stop: is preferably formed as a lateral spur on a threaded shank 'eter is provided, at which a keeperplate 38 is I attached by means of a screw 33 to the-upper face 7 of the plate It). This keeper'holds the nut" 36 l V in position. Beyond the reduced neck 31 .the

40 carrying a micrometer scale; between this dial 1? and the neck a cone face 4lisformed with scal lines registered with the.numbers on thedial and 'these scale lines may-register with a zero mark or base linei42 formed on the-keeper or i strap 38. Beyond the dial a knurled iheado r disc 43 is provided to facilitate the rotation of the" nut 36. to cause'the threaded shank 35 to move in or out to adjust the center stop 34- inwardly for. smaller drills; or outwardly for larger drillsi And, if desired,'the' upper end of the keeper plate 38 may be provided with a dowel pin 44 for asment. This plate 38 operates as a frictionbrake on the'collar 31 so that the collar 36'will remain 1. In guiding means for 2,3873%59 The grindi g wheel lmay be mounted in a bearingic, and its shaft mayrarrv a pulley 3b which can be rotated by a belt 311;. However, any:

suitable means may: be employed forrotating this grinding wheel. i a i i If desired, the intermediate circumferential zoneof the plate Ill may have a depressionbr recessrllla formed therein so thatthedrill is sup ported :on'the flatssurfaces or zones on opposite,10

sides of; this depression.

Many other embodiments of the invention may. be resortedto without departlngfrom the spirit of: the invention;

:.What I claim is: i r

ingof a drill-point on arr-abrading face, the combination of a relatively fixed rest having an upper face disposed in a plane inclined with relation to the abrading face against which the point of the drill is presented, said rest having a curved guide remote from the abrading face, a relatively fixed centering stop carried by the rest for guiding the side of the drill adjacent to, but removed from, its sharpened point so that the cone point of the drill is located between the stop and the abrading face; and means secured to the drill adjacent the said curved guide for riding along the same in sharpening the drill, all of said parts cooperating to enable the drill to be swung in each direction from its mid-position on the rest to sharpen the inclined face of the drill point on both sidesof its axis.

2. In guiding means for facilitating the grind ing of a drill-point on an abrading face, the combination of a relatively fixed rest having an upper face disposed in a plane inclined with relation to the abrading face against which the point of the drill is presented, said rest having a curved guide remote from the abrading face, a relatively fixed centering stop carried by the rest for guiding the side of the drill near its point and about which the forward end of the drill swings in the sharp-, ening movement; means for adjustably moving said centering stop laterally to adapt its position to the diameter of the drill being sharpened; and means secured to the drill and capable of being guided along said curved guide, said curved guide operating to permit the point of the drill to approach the said abrading face when the rear end of the drill is swung toward the abrading face while maintaining the point of the drill against said centering stop.

3. In guiding means for facilitating the grinding of a drill-point constructed as defined in claim 1, including adjusting means associated with the relatively fixed centering stop for adjusting the said stop laterally to adapt the said guiding means for grinding drills of different diameter, said adjusting means having a scale associated therewith, the reading on which operates as a guide for setting the centering stop to different positions to correspond with different drill diameters; said parts all cooperating so that the forward end of the drill swings around on the side of the stop during the sharpening movement of the drill.

4. In guiding means for facilitating the grinding of a drill-point on an abrading face, the combination of a relatively fixed rest having an upper face disposed in a plane inclined with relation to the abrading face against which the point of the drill is presented, said rest having a curved guide remote from the abrading face, a relatively fixed centering stop for engaging the side of the drill adjacent its point, said rest having guiding means facilitating the grind-k extending transversely thereon along which the centering stop may move, means for adjustin and indicating the position, of the stop in said guiding means to adapt the stop for grindingdrills of different diameters, and means secured to the, drill adjacent the said curved guide for riding along the same when sharpening the drill.

5. In guiding means forfacilitating the grind! ing of a drill-point against the substantially flat abrading side face of agrinding wheel, the combination of a relatively fixed rest, a holder unattached to the rest and capable of clamping the butt end of the drill, said rest having means for enabling the drill to be held on the rest with the axis of they drill inclined to the horizontal in the vertical plane passing through the axis of the drill and also in a plane that is'inclined .to the plane of the side face of the grinding wheel, a relatively fixed stop carried by the rest for engaging the side of the drill back from, but adjacent to, the sharpened point, said rest and said holder having cooperating means enabling the holder and the butt end of the drill to be swung laterally in both directions and toward the grinding face in grinding the drill-point.

6. In guiding means for facilitating the grinding of a drill-point on an abrading face, the combination of a relatively fixed rest having an upper face disposed in a plane inclined with relation to the said abradingface, a centering stop mounted on the rest with means for adjusting the same laterally on the rest and toward or from the grinding face to adapt the position of the stop for grinding the points of drills of different diameters, said rest having a curved guiding edge located on its side remote from the grinding face, and a holder for clamping the body of the drill when the drill is held lying on the rest, the forward end of the said holder having means for engaging said curved edge when the holder is swung laterally and toward the grinding face to grind the drill-point.

'7. In guiding means for facilitating the grinding of a drill-point on a grinding wheel, the combination of a rest supported with an edge adjacent the face of the wheel, said rest operating as a guide for a drill holder independent of the rest, supported in the operators hand, said rest having a curved guide edge remote from the wheel against which the operator presses the forward end of the holder, and a center stop projecting up from the rest adjacent the first-named edge for engaging one side only of the drill-point when the drill is held on the rest and pressed against said curved guide edge, said curved guide operating to permit the drill-point to swing around it and to approach and engage the face of the wheel when the butt end of the drill is swung toward the wheel.

8. In guiding means for facilitating the grinding of a drill-point on an abrading face, the combination'of a relatively fixed rest having an upper face disposed in a plane inclined with relation to the said abrading face, said rest having a curved guide remote from the abrading face, a holder for carrying the butt portion of the drill,

- said holder being independent of the said rest,

for engaging and riding along the said curved guide when grinding the drill-point, and means carried by the rest and projecting above the plane of the-upper face of the rest for guiding the side of the drill adjacent to,'but removed from, its sharpened point, to determine the position of the axis of the drill when the said holder is applied to said curved guide preparatory to grinding the drill-point. t

.9. In guiding means for facilitating the grinding of a drill-point on an abrading face, the combination of a relatively fixed rest having aniupper face disposed in a. plane inclined with relation to the said abrading face, said rest having a curved guide remote from the abrading face, a holder for attachment to the butt portion of the drill, said holder being independent of the said point.

rest, freely movable, and portable in the operator's hand so thatit may be pressed down'by manual force against said rest, said holder includinga body and a gauge member pivotally mounted 1 on the body of the holder, capable of assuming a capable of being swung around to another position adjacent the rear end of the holder when the holder is to be'guided along the curved guide when grinding the drill-pointsaid holder having means at its forward end for engaging and riding along on said curved guide when grinding the drill- ALBERT c. MOOREFIELD. 

